30 PLANT-LIFE ON LAND [CH. 



America, it extends through the Southern Hemi- 

 sphere to New Zealand. It is true that in these 

 distant lands the type may differ from our own 

 Bracken in minor details, but the differences are 

 held to be only varietal, and the species designated 

 Pteridium aquilinum or better known under its 

 old name of Pteris aquilina may properly be recog- 

 nised as cosmopolitan. Where it occurs it is commonly 

 found in quantity, indeed it has been described by 

 Dr Christ as the gregarious Fern par excellence. 

 And so we see it sometimes growing with us so densely 

 as to occupy the ground to the exclusion of all else. 

 This is notably the case where the soil is sandy, and 

 free from lime. 



Wading through Bracken as high as one's waist it 

 may be a surprise to be told that all that we see 

 above ground is the leafage, and that the stem which 

 bears the leaves is entirely concealed. But if you 

 take the trouble to dig the plant up you will find 

 some inches below the surface of the soil an elongated, 

 horizontally running stock about half an inch in 

 diameter or less, dark brown in colour, and marked 

 laterally by two paler lines. From this the leaves 

 arise alternately on either side (Fig. 4). The growing 

 tip of the stock is covered with a dense mat of hairs, 

 and near to it one or two young leaves may be seen. 

 Further from the tip there will be found the stalks of 

 one, or at most two leaves of the current season whose 



